Back up light switch mounting and wiring help?

[73QCodeMach1F]

I have a 73 Mach 1 4 speed top loader car, inherited from my late grandfather, before he passed away he was in the process of trying to install a backup camera in the car and somewhere along the way disconnected the reverse light switch, so I have no back up lights. I have the switch ordered from NPD but I’m at a loss as to how it actually connects. There’s no mounting bracket that I can find, there’s no electrical connection for it to plug into except for a plug hanging down at the back of the engine in front of the trans that’s going to nothing. I’m guessing there is an extension harness that hopefully would run from that plug back to the switch. If anyone has any pictures and or a shop manual schematic showing exactly how this should go, please help. Attached pictures of what the back of trans and shifter looks like, and plug end hanging down.

 

[73QCodeMach1F]

More pics

 

[Steve McMahan]

I’m not certain this will help, buts it’s information:

https://7173mustangs.com/threads/4-speed-toploader-backup-switch-connection.39292/

 

[Hemikiller]

That's not a factory Ford shifter. Guessing it's from a GM product. The factory shifter has the reverse light mount built into the back plate. The handle also slides into a receiver, yours is bolted on with a home made spacer.

You can get the Hurst aftermarket reverse light bracket/switch that bolts under the (missing) stop bolt and make it work.

https://www.holley.com/products/dri...accessories/shifter_accessories/parts/2480003

 

[73QCodeMach1F]

That's not a factory Ford shifter. Guessing it's from a GM product. The factory shifter has the reverse light mount built into the back plate. The handle also slides into a receiver, yours is bolted on with a home made spacer.

You can get the Hurst aftermarket reverse light bracket/switch that bolts under the (missing) stop bolt and make it work.

https://www.holley.com/products/dri...accessories/shifter_accessories/parts/2480003

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You are a lifesaver! I actually found a few pictures that showed a switch that looked like that Hurst shifter switch. Couldn’t find any of the factory set up so I had no idea what I was missing. Makes sense now. So basically just use the same harness as factory and just cut the end off that would go to the factory switch, attach wires to the new switch?

 

[Hemikiller]

Yep, that's pretty much it. If you don't want to cut the factory harness, make a couple jumpers.

 

[73QCodeMach1F]

Yep, that's pretty much it. If you don't want to cut the factory harness, make a couple jumpers.

Perfect, thanks for your help! I was absolutely stumped. I have a few friends who own 71-73s and their explanation of how the factory switch should go, they were making it sound so easy.. sure would be if I had that dang bracket on mine!

 

[73QCodeMach1F]

Any pictures of where the extension harness ties into the main harness? I still have yet to find that.

 

[Hemikiller]

The backup light harness plugs into the engine compartment harness behind the driver's valve cover.

 

[73QCodeMach1F]

Finally making progress. I saw that plug earlier and thought it was for something else since I never found the other end. Traced it through the firewall and it goes up and over the steering column and down under the carpet by the floor dimmer switch. Will remove kick panel and rocker trim and hopefully find the plug tucked in there somewhere.

 

[midlife]

Finally making progress. I saw that plug earlier and thought it was for something else since I never found the other end. Traced it through the firewall and it goes up and over the steering column and down under the carpet by the floor dimmer switch. Will remove kick panel and rocker trim and hopefully find the plug tucked in there somewhere.

Huh? The NSS/BU harness doesn't go through the firewall at all: from the plug at the engine side of the firewall, it goes down to the transmission.
Maybe I don't understand what you're trying to say...

 

[73QCodeMach1F]

Huh? The NSS/BU harness doesn't go through the firewall at all: from the plug at the engine side of the firewall, it goes down to the transmission.
Maybe I don't understand what you're trying to say...

This particular one does for whatever reason, will find out why later when I take apart the interior. I have no plug at all coming down to the shifter area, either under the car or through the interior under the dash. This is the wire going to that plug in the engine bay.

 

[Hemikiller]

Whatever that is running under the steering column, it's not a factory setup. The backup light harness plugs into the 4-way square plug at the firewall, then down the transmission to the shifter. Maybe the PO ran the harness inside the car to turn on the reverse lights manually, the 'ol "wanna race" signal.

 

[73QCodeMach1F]

Whatever that is running under the steering column, it's not a factory setup. The backup light harness plugs into the 4-way square plug at the firewall, then down the transmission to the shifter. Maybe the PO ran the harness inside the car to turn on the reverse lights manually, the 'ol "wanna race" signal.

To reiterate a little bit, the car was previously my grandpa’s car. In 2016 he was diagnosed with cancer, at the time he was in the process of trying to wire in a back up camera. When he passed, the drivers side rocker panel trim was out, carpet pulled back and wiring all over the place. My dad ended up putting things "back together" and since then, no backup lights due to the obvious lack of the switch, god only knows where my grandpa put it, or which type he had. If it was the aftermarket hurst switch which I will have to get, or something that was custom made. All I know is prior to him getting sick and taking things apart, they were working. As to previous wire routing, that’s also unknown if it’s either something he routed that way or even the owner before him. He was 3rd owner of the car.

 

[Mark873]

I found this on Amazon, trying to get this out to anyone dealing with wiring and vacuum. "1973 Colorized Mustang Wiring Diagrams Kindle Interactive Edition" $12.95 for downloading to Kindle. Best I have found.